Field of the Invention
The present invention relates to a system that performs fluoroscopic imaging on an inspected object from two or more different angles by using an X-ray with two or more different energies respectively, in particular, to a system that performs fluoroscopic imaging by using a high energy X-ray generated by a high energy electron accelerator in nondestructive flaw detection, fluoroscopic imaging, as well as security inspection apparatuses used for large scale container inspection, vehicle inspection, air cargo inspection, train inspection etc.
Description of the Related Art
X-ray is widely used in fields such as industrial nondestructive detection, security inspection etc. For large scale inspected objects, for example, boilers, airspace engines, bulk goods at airports/railways/customs, whole goods of cars/trucks/containers/trains etc., a high energy X-ray, which is generally generated by using an electron accelerator with an energy higher than 2 MeV, is required to be used for their fluoroscopic inspection. The basic method for an electron accelerator to generate an X-ray is as follows: generating an electron beam with an electron gun, accelerating the electron beam with an electric field so that it obtains a high energy, and generating an X-ray by bombarding a target with the high energy electron beam. A high energy X-ray fluoroscopic imaging system utilizes the high-penetration ability of an X-ray. When an X-ray penetrates an inspected object, its intensity will reduce, and the degree of reduction is related to the density, shape, thickness, substance material and the like of the inspected object. The intensity information of the X-ray after penetrating the inspected object is obtained with a detector, and is subjected to processes such as signal processing, algorithm analysis, image reconstruction and the like so as to obtain a fluoroscopic image reflecting the information such as the shape, structure and even the substance material of the inspected object, thereby goals such as structure analysis, flaw inspection, name and type inspection of goods, dangerous goods recognition, prohibited goods inspection and the like are achieved.
Chinese Patent “Method and System for Scanning Radiation Imaging with Double Viewing Angles (Patent No. CN101210895)” discloses a specific method in which two X-ray beams are generated by using one radiation source to perform fluoroscopic imaging on an inspected object and a multi-level image is constructed. This is a low-cost, convenient, and fast deep-recognition method.
Furthermore, Chinese Patent “Multiple Energy Double Frequency Particle Accelerator and Method thereof (Patent No. CN101163372)” discloses a technology that utilizes an electron accelerator to generate electron beams and X-rays with a number of different energies at different time; and Chinese Patents “Apparatus and Method for Generating an X-ray with Different Energies and Material Recognition System (Patent No. CN101076218)”, “Method for Radiation Scanning Substance with Multiple Energies and Apparatus thereof (Patent No. CN1995993)”, “Method and Apparatus for Substance Recognition (Patent No. CN101435783)” and the like disclose a method in which an inspected object is subjected to fluoroscopic imaging with high energy X-ray and low energy X-ray so as to obtain a fluoroscopic image and materiel information of the inspected object.
Moreover, Chinese Patent “Method and System for Materiel Recognition with Double-Viewing-Angle Multiple-Energy Fluoroscopic Image (Patent No. CN101358936)” discloses a method in which symmetric X-ray beams (with symmetric positions, identical energies, identical intensities etc.) are obtained by two collimators using a multiple energy electron accelerator as the radiation source, thereby a fluoroscopic image with double viewing angles and multiple energies is achieved. This is a combination of the above two types of patent technologies. Here, the multiple energy electron accelerator refers to an accelerator that can output X-rays with different energies at different time, such as the technologies disclosed in Chinese Patents CN101163372 and CN101076218. Although there are two collimators, the X-rays obtained by the two collimators are of the same characteristics.